不同铁源对剩余污泥厌氧系统中蓝铁石生成的影响  

Effects of different external irons on vivianite formation during the anaerobic fermentation of waste activated sludge

作　　者：胡德秀[1] 闫怡心 李瑶[1] 朱念 张聪 HU Dexiu;YAN Yixin;LI Yao;ZHU Nian;ZHANG Cong(State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi’an University of Technology,Xi’an 710048)

机构地区：[1]西安理工大学省部共建西北旱区生态水利国家重点实验室,西安710048

出　　处：《环境科学学报》2022年第8期347-355,共9页Acta Scientiae Circumstantiae

基　　金：省部共建西北旱区生态水利国家重点实验室基金资助项目(No.2016ZZKT-8);水利水电学院国家级实验教学示范中心项目(No.WRHE1709)。

摘　　要：以污水处理厂剩余污泥为研究对象,污泥经酸/碱预处理(pH=3.0/pH=10.0)后,分别以FeOOH、FeCl_(3)及Fe_(2)O_(3)为外加铁源,进行厌氧发酵,探究铁源对厌氧系统中蓝铁石晶体生成的影响.结果表明:FeCl_(3)和FeOOH可以高效地被还原为Fe^(2+),其铁还原效率(EFe)最高为56.24%~80.10%,且酸处理效果优于碱处理(3.00%~13.31%),而Fe_(2)O_(3)的EFe相对较低,最高分别为31.94%(pH=3.0)和50.1%(pH=10.0).FeOOH和Fe_(2)O_(3)的投加,可促进胞外聚合物(EPS)中蛋白质含量的提升,增强胞外电子传递能力,但Fe_(2)O_(3)因其结晶度高,阻碍了铁还原微生物对铁源的利用,导致铁还原效率低.上清液PO_(4)^(3-)浓度、污泥Fe-P比例与EFe呈负相关,EFe越高则PO_(4)^(3-)浓度、Fe-P比例越低.FeOOH组上清液PO_(4)^(3-)浓度下降幅度最大,反应第9 d PO_(4)^(3-)浓度最低,仅为对照组的10.30%(pH=3.0)和17.20%(pH=10.0),其次是FeCl_(3)组(22.83%/27.87%),Fe_(2)O_(3)组最终剩余较多PO_(4)^(3-)(65.02%/56.33%);FeOOH、FeCl_(3)和Fe_(2)O_(3)酸/碱组的Fe-P比例分别为32.19%/21.20%、34.41%/23.09%和20.92%/11.99%.铁源的添加提高了污泥的磷回收率(Rp),并且酸预处理效果优于碱处理,其中FeCl_(3)组Rp最高,是对照组的2.91倍,其次是FeOOH组(2.63倍)和Fe_(2)O_(3)组(2.12倍).XRD分析表明,FeOOH和FeCl_(3)酸/碱预处理组均生成了蓝铁石晶体.In oder to investigate the effects of external irons on vivinaite formation during anaerobic fermentation(AF),the waste activated sludge(WAS)from wastewater treatment plant was selected as a sample.After performing acid/alkali pretreatment(pH=3.0/pH=10.0)on WAS,FeOOH,FeCl_(3) and Fe_(2)O_(3) were added as external irons,respectively.The results indicated that FeCl_(3) and FeOOH can be reduced to Fe^(2+)efficiently and the maxium iron reduction efficiency(EFe)ranged from 56.24%to 80.1%.Furthermore,EFe of acid treatment groups was 3.00%~13.31%higher than that of alkali treatment.The EFe of Fe_(2)O_(3) was 31.94%(pH=3.0)and 50.10%(pH=10.0).The addition of FeOOH and Fe_(2)O_(3) promoted the increase of protein in the extracellular polymeric substances(EPS)of WAS during AF,which enhanced the ability of extracellular electron transfer.However,the degree of iron reduction of Fe_(2)O_(3) group is weak,because its high crystallinity prevented iron-reducing bacteria from utilizing iron.The concentration of PO_(4)^(3-)in supernatant and the ratio of Fe-P in WAS was negatively correlated with EFe.The higher the EFe,the lower the concentration of PO_(4)^(3-)and the ratio of Fe-P.The concentration of PO_(4)^(3-)in the supernatant of FeOOH group decreased and reached the minimum on 9th day,accounting for 10.30%(pH=3.0)and 17.20%(pH=10.0)of control group,followed by FeCl_(3)(22.83%/27.87%)and Fe_(2)O_(3) groups(65.02%/56.33%).The ratios of Fe-P of FeOOH,FeCl_(3) and Fe_(2)O_(3)(acid/alkali pretreatment)groups were 32.19%/21.20%,34.41%/23.09%and 20.92%/11.99%,respectively.The addition of iron increased the phosphorus recovery rate(Rp)of WAS,and the efficiency of acid pretreatment was better than that of alkali treatment.The Rp of FeCl_(3) with acid pretreatment group was the highest,which was 2.91 times that of control group,followed by FeOOH(2.63 times)and Fe_(2)O_(3) groups(2.12 times).The results of XRD analysis showed that both FeOOH and FeCl_(3) with acid/alkali pretreatment groups produced vivianite crystals.

关 键 词：剩余污泥 厌氧系统 铁源 磷回收 蓝铁石 

分 类 号：X705[环境科学与工程—环境工程] TU992.3[建筑科学—市政工程]